SURVEY PART ONE: DAMSELFLIES, BUT NO TURTLES

THERE IS ANOTHER DAMSELFLY PHOTO  FOR YOU TO ENJOY LATER IN THE BLOG !  

      It is always best to start out on a positive note and these pictures are a good example of what we found. There were emerging and copulating damselflies scattered throughout the area and I could not resist spending time with them. In the next installment of the blog there will be more pictures and a discussion of the life history of Odonata.

      However, for now I will touch on some important things about them. The order Odonata includes Zygoptera (dragonflies) and Anisoptera (damselflies) and they are predators whether they are adults or immature. Adults eat a variety of small flying insects including mosquitos and the immature form, called a naiad not nymph, have a voracious appetite. For example, they eat small worms, fish, mollusks, and even small fish or tadpoles. The female  lays eggs singly rather than in a cluster and I will show that and more tomorrow.

More than one-half of the reach of Santa Rosa Creek we surveyed yesterday is approximately 1 - 1.5 meters wide, shallow, and fast-moving. The shallow fast moving water is not good foraging area and there are no pools with suitable basking sites. Finally, to the right of the Kate is a flat, cobblestone open area where mountain bikers, dogs and hikers routinely travel. This kind of activity makes it even more likely that western pond turtles are not living along this section.

     

     The primary task yesterday was to find a place to set hoop traps to get more turtles and the best way to do that is walk the creek and listen for them. No, the do not have a call like a bird, what you listen for is the special "plop" sound they make when they drop off a log or rock into the water while basking. They have good eyesight and hearing, so when a predator such as a human gets too close, they drop into the water with a distinctive sound. Generally, western pond turtles have an foraging area that is rich in bankside vegetation that provides habitat for their food resources (crayfish, insects, worms, and snails). In addition, they have one or more basking sites that may be a log, rock, an isolated bank, or even floating vegetation where they warm themselves so they can digest their food. Remember, they are ectothermic, meaning they use the sun to bring their raise their body temperature high enough for physiological processes such as digestion. To regulate their temperature they move in and out of the water or shade. Basking sites whether they are a rock, log, or along the bank, have one particular requirement, a deep pool to escape into. Thus, in addition to listening for their "plop" we also are looking for basking sites. Unfortunately, yesterday we did not find suitable basking sites and much of the creek is either too narrow, dark, or exposed to human activity. 

    My second goal is to sample the habitat to determine the availability western pond turtle food resources was quite successful and we are processing these samples over the next two or three days.      

     Although it is inviting to just plunge ahead and keep searching for turtles and places to trap, I prefer to take time to look at my samples, review the photographs I took, and my field notes. This kind of evaluation helps me determine if the processes I am using are effective and my conclusions are accurate. One of the worst things that can happen when I do this kind of work is to discovering something important was omitted when I am evaluating data or writing about the results.

This is an example of what the remaining parts of Santa Rosa Creek. The  fundamental geomorphology (i.e., bank height, channel width, and composition) is the same but it is darker and less likely to have food resources and there are no basking sites.

     Although there were no signs of western pond turtles, there is abundant evidence that the North American river otter (Lontra canadensis) is foraging in the area. In addition, a shy female Mallard duck (Anas platyrhynchos) and her seven or so ducklings make this there home.

Because of the abundance of  scats and crayfish remains, it is clear North American river otter's are foraging here.

     Lastly, it is helpful to understand the amount of water that flows through here in the winter during and after rain events. Debris well over two meters above the substrate of the creek hangs in the trees indicates how high the water rises.

This wide angle photograph with Kate in the background,  shows debris hanging in the branches (outlined) in a 1 meter deep lagoon.  The highest cluster is at least a foot beyond my fingertips and I am 5"6" tall, so it is well over eight feet. Hence, the entire area below the highest piece of debris is under fast moving water in the winter. Something to think about! I will cover the subject in detail later.

HERE IT IS !